@article{b0736f526dba420690fad1bbb425c861,
title = "Direct Observation of Coherent Longitudinal and Shear Acoustic Phonons in TaAs Using Ultrafast X-Ray Diffraction",
abstract = "Using femtosecond time-resolved x-ray diffraction, we investigated optically excited coherent acoustic phonons in the Weyl semimetal TaAs. The low symmetry of the (112) surface probed in our experiment enables the simultaneous excitation of longitudinal and shear acoustic modes, whose dispersion closely matches our simulations. We observed an asymmetry in the spectral line shape of the longitudinal mode that is notably absent from the shear mode, suggesting a time-dependent frequency chirp that is likely driven by photoinduced carrier diffusion. We argue on the basis of symmetry that these acoustic deformations can transiently alter the electronic structure near the Weyl points and support this with model calculations. Our study underscores the benefit of using off-axis crystal orientations when optically exciting acoustic deformations in topological semimetals, allowing one to transiently change their crystal and electronic structures.",
author = "Lee, {Min Cheol} and N. Sirica and Teitelbaum, {S. W.} and A. Maznev and T. Pezeril and R. Tutchton and V. Krapivin and {De La Pena}, {G. A.} and Y. Huang and Zhao, {L. X.} and Chen, {G. F.} and B. Xu and R. Yang and J. Shi and Zhu, {J. X.} and Yarotski, {D. A.} and Qiu, {X. G.} and Nelson, {K. A.} and M. Trigo and Reis, {D. A.} and Prasankumar, {R. P.}",
note = "Funding Information: This work was performed at the Center for Integrated Nanotechnologies at Los Alamos National Laboratory (LANL), a U.S. Department of Energy, Office of Basic Energy Sciences user facility, under user proposal 2018BU0083. It was primarily supported through the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering via FWP No. 2018LANLBES16 (M.-C. L. and R. P. P.), Contract No. DE-AC02-76SF00515 (S. T., V. K., Y. H., M. T., and D. A. R.) and Contract No. DE-SC0019126 (A. M., T. P., J. S., and K. A. N.). Use of the L. C. L. S. is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. J.-X. Z. and D. A. Y. are supported by the Center for Advancement of Topological Semimetals, an Energy Frontier Research Center funded by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, through the Ames Laboratory under its Contract No. DE-AC02-07CH11358. N. S. was supported by the LANL LDRD program. This research used resources at the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. We appreciate Matthieu Chollet{\textquoteright}s assistance in performing experiments at the LCLS XPP beamline. Publisher Copyright: {\textcopyright} 2022 American Physical Society.",
year = "2022",
month = apr,
day = "15",
doi = "10.1103/PhysRevLett.128.155301",
language = "English (US)",
volume = "128",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "15",
}